The periodontal disease process is a microbially driven destructive inflammatory disease. Of the almost 300 different bacterial species which may occupy a developing periodontal pocket, a small number are potentially significant periodontopathogens. Among these, members of the genera Bacteroides, Actinobacillus, Wolinella, Eikenella, and Capnocytophaga are important contributors to periodontal pathogenesis. Interaction of these bacteria with the host usually is mediated through the bacterial cell surface. We have already determined that the outer membrane of several of these putative periodontopathogens contains virulence factors which may adversely affect the host. Lipopolysaccharide, outer membranae per se, outer membrane vesicles, and peptidoglycan may be significant contributors to the periodontal disease process. Chemical and immunobiological analysis of these components, especially the outer membrane and LPS reveals that they contain unique constituents. The BASIC THEME OF THIS COMPETITIVE RENEWAL IS TO INVESTIGATE THE CHEMISTRY AND IMMUNOBIOLOGY OF THE BACTERIAL SURFACE OF THESE SELECTED PERIODONTOPATHOGENS, so as to devise strategies for interfering with the deleterious interaction of these bacterial pathogens or their components with the host and host tissue. It is therefore the objective of this competitive renewal application to: (1) determine the distribution of major outer membrane antigens in selected Bacteroides, Wolinella and Eikenella strains; (2) to dissect the lipopolysaccharides form these pathogens in order to determine their virulence potential in selected in vitro assays of biological activity relevant to periodontal inflammation and connective tissue destruction; and (3) to determine the effect of carbon and nitrogen, as well as host-derived components on the chemistry and virulence potential of the outer membrane, restricted growth conditions as well as in batch culture; and (4) to create an animal model of bacterial pathogenesis and utilize monoclonal antibodies as immunological probes to study the virulence potential of specific components of the bacterial cell envelope.